Drilling rigs used in drilling oil and gas wells employ a kelly joint that may be either square or hexagonal in cross section. The kelly joint is connected to a drill string on the lower end and is connected to a fluid swivel joint at the upper end. The kelly joint is provided with a drive bushing that connects through a rotary table at the derrick floor level and can move vertically through the drive bushing to impart rotation to the drill string. It is old as indicated in U.S. Pat. Nos. 3,144,085 and 3,212,578 to provide a power spinner for rotating the kelly joint for connecting and disconnecting the kelly joint from the drill string.
The present invention is directed to an improved power spinner including moving the actuating gears laterally toward and away from each other for providing a strong driving action yet one which avoids clashing of gears.